This specification relates to text classification using data processing systems.
Text classification systems can classify pieces of electronic text, e.g., electronic documents. For example, text classification systems can classify a piece of text as relating to one or more of a set of predetermined topics. Some text classification systems receive as input features of the piece of text and use the features to generate the classification for the piece of text.
Neural networks are machine learning models that employ one or more layers of models to generate an output, e.g., a classification, for a received input. Some neural networks include one or more hidden layers in addition to an output layer. The output of each hidden layer is used as input to the next layer in the network, i.e., the next hidden layer or the output layer of the network. Each layer of the network generates an output from a received input in accordance with current values of a respective set of parameters.